ANTIRABIC SERUM. 513 



17,337 cases were treated, with a mortality of .48 per cent. It has 

 been alleged that many people are treated who have been bitten by 

 dogs that were not mad. This, however, is not more true of the 

 cases treated by Pasteur's method than it was of those on which the 

 ordinary mortality of 1 6 per cent was based, and care is taken in 

 making up the statistics to distinguish the cases into three classes. 

 Class A includes only persons bitten by dogs proved to have had 

 rabies, by inoculation in healthy animals of parts of their central 

 nervous system. Class B includes those bitten by dogs that a com- 

 petent veterinary surgeon has pronounced to be mad. Class C 

 includes all other cases. During 1895., 122 cases belonging to Class 

 A were treated, with no deaths ; 949 belonging to Class B, with two 

 deaths ; and 449 belonging to Class C, with no deaths. Besides the 

 Institute in Paris, similar institutions exist in other parts of France, in 

 Italy, and especially in Russia, as well as in other parts of the world ; 

 and in these similar success has been experienced. It may be now 

 taken as established, that a very grave responsibility rests on those 

 concerned, if a person bitten by a mad animal is not subjected to the 

 Pasteur treatment. 



Antirabic Serum. In the early part of the present 

 century an Italian physician, Valli, showed that immunity 

 against rabies could be conferred by administering through 

 the stomach progressively increasing doses of hydrophobic 

 virus. Following up this observation, Tizzoni and Cen- 

 tanni have attenuated rabic virus by submitting it to peptic 

 digestion, and have immunised animals by injecting gradu- 

 ally increasing strengths of such virus. This method is 

 usually referred to as the Italian method of immunisation. 

 The latter workers showed from this that the serum of 

 animals thus immunised could give rise to passive im- 

 munity in other animals ; and further, that if injected into 

 animals from 7 to 14 days after infection with the virus, 

 it prevented the latter from producing its fatal effects, even 

 when symptoms had begun to manifest themselves. They 

 further succeeded in producing in the sheep and the dog 

 an immunity equal to from 1-25,000 to 1-50,000 (vide 

 p. 473), and they recommended the use, in severe cases, 

 of the serum of such animals in addition to the treatment 

 of the patient by the Pasteur method. We do not, of 

 course, know whether the serum contains antitoxic or anti- 

 microbic bodies. 



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